Agreement of the Resting Distal to Aortic Coronary Pressure With the Instantaneous Wave-Free Ratio

J Am Coll Cardiol. 2017 Oct 24;70(17):2105-2113. doi: 10.1016/j.jacc.2017.08.049.

Abstract

Background: Recently, 2 randomized controlled trials showed that the instantaneous wave-free ratio (iFR), a resting coronary physiological index, is noninferior to fractional flow reserve for guiding revascularization. The resting distal to aortic coronary pressure (Pd/Pa) measured at rest is another adenosine-free index widely available in the cardiac catheterization laboratory; however, little is known about the agreement of Pd/Pa using iFR as a reference standard.

Objectives: The goal of this study was to investigate the agreement of Pd/Pa with iFR.

Methods: A total of 763 patients were prospectively enrolled from 12 institutions. iFR and Pd/Pa were measured under resting conditions. Using iFR ≤0.89 as a reference standard, the agreement of Pd/Pa and its best cutoff value were assessed.

Results: According to the independent core laboratory analysis, iFR and Pd/Pa were analyzable in 627 and 733 patients (82.2% vs. 96.1%; p < 0.001), respectively. The median iFR and Pd/Pa were 0.90 (interquartile range: 0.85 to 0.94) and 0.92 (interquartile range: 0.88 to 0.95), and the 2 indices were highly correlated (R2 = 0.93; p < 0.001; iFR = 1.31 * Pd/Pa -0.31). According to the receiver-operating characteristic curve analysis, Pd/Pa showed excellent agreement (area under the curve: 0.98; 95% confidence interval: 0.97 to 0.99; p < 0.001) with a best cutoff value of Pd/Pa ≤0.91. The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 93.0%, 91.4%, 94.4%, 93.3%, and 92.7%, respectively. These results were similar in patients with acute coronary syndrome and stable angina.

Conclusions: Pd/Pa was analyzable in a significantly higher number of patients than iFR. Pd/Pa showed excellent agreement with iFR, suggesting that it could be applied clinically in a similar fashion. (Can Contrast Injection Better Approximate FFR Compared to Pure Resting Physiology? [CONTRAST]; NCT02184117).

Keywords: fractional flow reserve; instantaneous wave-free ratio; resting distal to aortic coronary pressure.

MeSH terms

  • Aged
  • Blood Pressure / physiology*
  • Blood Pressure Determination / methods
  • Coronary Circulation / physiology
  • Coronary Vessels / physiology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Prospective Studies
  • Reference Standards

Associated data

  • ClinicalTrials.gov/NCT02184117